There are various commercially available hard surface cleaning compositions consisting of small amounts of different surfactants, including nonionic and anionic detergents, solvents such as alcohols, glycol ethers, and alkaline constituents in water. However, the cleaning efficiency of these detergents results in minimal removal of a film thought to be electrostatically held to the hard surface. This film is commonly referred to as "road film" in the industry. Moreover, many of these cleaners necessitate repeated passes with a cleaning cloth or other sorbent to remove this film. Thus, although there are a number of consumer cleaning products, these products require brushing, scrubbing, or some other manual action while the cleaner is in the wet state to achieve effective cleaning. As a consequence, the purpose of this invention is the development of an aqueous cleaning composition which provides good results and requires no manual action other than a high pressure rinse while the cleaner is in the wet state.
For example, attempts to avoid some of these problems are suggested by U.S. Pats. Nos. 4,213,873 and 4,315,828, wherein relatively high molecular weight glycols, e.g., polymeric glycols, are used as a cleaning agent in combination with ammonia hydroxide, alcohols, and water as the solvent. However, to avoid streaking, it was necessary to thoroughly wipe the surface in order to loosen the soil into the cloth; otherwise, a residue generally remained on the surface.
Metal surfaces, and particularly aluminum and aluminum alloys, are presently cleaned with aqueous solutions of acid, including sulfuric acid and hydrofluoric acid, together with one or more surface-active agents or detergents. While these acid solutions are effective and have many advantages, there are many disadvantages associated with acid cleaning. For example, these acids are capable of dissolving most metals commonly utilized in cleaning equipment. Moreover, hydrofluoric acid is particularly unsatisfactory, since the acid and the rinse water containing the acid present environmental problems and are extremely dangerous to personnel.
To avoid the disadvantages of acid cleaners, various alkaline compositions have been formulated to eliminate the problems encountered with utilizing acids. The alkaline materials, however, raise new problems which have militated against their use commercially. For example, the use of alkali metal hydroxides may result in extensive etching of the metal, e.g., aluminum surfaces. There are a number of patents which disclose neutral or alkaline cleaning compositions for metal surfaces, including U.S. Pats. Nos. 3,975,215; 4,093,566; and 4,477,290. These patents suggest the use of an alkali metal hydroxide in combination with chelating agents and one or more anionic or nonionic surfactants.